The present invention generally relates to a method of forging steel components. More particularly, the present invention relates to hotformed irregularly shaped forgings and a method of forging irregularly shaped components.
Automobile and other industrial applications often require suspension or power transmission components to be structurally robust in order to react or transmit relatively high loads. Due to the high load requirements, these parts are often constructed from steel using a forging process. With the cost of steel rapidly increasing in today's market, it has become desirable to reduce the amount of steel scrap generated when manufacturing a steel structural component.
For certain irregularly shaped components such as hubs, spindles, flanges and gears, previously known forging methods often require subsequent trimming and/or machining operations to remove flash generated during the forging operation. In one example, a component with radially outwardly and circumferentially spaced apart protrusions is constructed via a forging process depicted in FIG. 1. The known process begins by shearing a length of substantially cylindrically shaped material to a predetermined length to form a billet 4. The billet 4 is heated and placed within a forging die to form a reduced length structure having an increased diameter called a bust 5. The bust 5 is placed into a subsequent forging die cavity to further shape the material into a finished forging 6. The finished forging 6 may include a trim ring (flashing) 7 comprised of radially extending flashing several millimeters thick. The flashing extends from a minor diameter of the part up to and sometimes beyond a major diameter of the finished component. The flashing may be formed as a ring or smaller several segments depending on the finished component design.
The flashing is necessary to assure that the extremities of the die cavity are filled with steel. As such, known forging dies include passageways for the steel to flow between and around the radially extending protrusions. While this process is effective to increase the likelihood that the areas of the die cavities including the radially extending protrusions are properly filled, this process creates a relatively large amount of scrap for each component produced. For example, typical flashing can range in weight from 50 grams to 400 grams or more, depending on the size of the part.
After the forging process is completed, the finished forging with flashing is transferred to a trimming and piercing station where the flashing 7 is removed using a trim die and a punch. The part also undergoes a piercing operation where a slug 8 of material is removed to form a through aperture, if desired. The removed material is scrap. After cooling, the trimmed part is cleaned by means of shot blasting or another suitable method. Lastly, the part is machined into a final shape.
While the above-described process is useful for manufacturing forged components, improvement in the part and process may be realized. For example, it may be advantageous to produce an irregularly shaped forging having a reduced quantity of flashing. A reduced amount of flashing may reduce the final component cost by reducing the scrap generated during the manufacturing process.
Furthermore, it may be advantageous to define a process for forging a component having a reduced number of process steps. A reduced number of steps may reduce the complexity and the time required to complete the forging process.
The forging method of the present invention eliminates the need for a trimming step as previously required and also greatly reduces the quantity of steel converted to scrap during the manufacturing process of forging an irregularly shaped component. Specifically, a method of manufacturing an irregularly shaped forging includes heating a billet to a predetermined temperature, placing the heated billet within a cavity of a die set having a punch and a die, advancing the punch of the die set into the cavity to begin to displace the material into a plurality of radially extending and circumferentially spaced apart extremities of the cavity, and continuing to advance the punch into the die to force a portion of the material to enter predetermined clearance zones between the punch and die. The predetermined clearance zones are circumferentially spaced apart and positioned between the extremities of the cavity to form an irregularly shaped forging pattern having a plurality of axially extending flash sections positioned between radially extending pad sections of the irregularly shaped forging.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.